title: Management of hyperthyroidism during pregnancy and lactation.
abstract: BACKGROUND
  Poorly treated or untreated maternal overt hyperthyroidism may affect pregnancy outcome. Fetal and neonatal hypo- or hyper-thyroidism and neonatal central hypothyroidism may complicate health issues during intrauterine and neonatal periods.
  
  
  OBJECTIVE
  To review articles related to appropriate management of hyperthyroidism during pregnancy and lactation.
  
  
  METHODS
  A literature review was performed using MEDLINE with the terms 'hyperthyroidism and pregnancy', 'antithyroid drugs and pregnancy', 'radioiodine and pregnancy', 'hyperthyroidism and lactation', and 'antithyroid drugs and lactation', both separately and in conjunction with the terms 'fetus' and 'maternal.'
  
  
  RESULTS
  Antithyroid drugs are the main therapy for maternal hyperthyroidism. Both methimazole (MMI) and propylthiouracil (PTU) may be used during pregnancy; however, PTU is preferred in the first trimester and should be replaced by MMI after this trimester. Choanal and esophageal atresia of fetus in MMI-treated and maternal hepatotoxicity in PTU-treated pregnancies are of utmost concern. Maintaining free thyroxine concentration in the upper one-third of each trimester-specific reference interval denotes success of therapy. MMI is the mainstay of the treatment of post partum hyperthyroidism, in particular during lactation.
  
  
  CONCLUSIONS
  Management of hyperthyroidism during pregnancy and lactation requires special considerations and should be carefully implemented to avoid any adverse effects on the mother, fetus, and neonate.
authors.affiliation: Research Institute for Endocrine Sciences, Endocrine Research Center, Shahid Beheshti University, PO Box 19395-4763, Tehran 198517413, Islamic Republic of Iran. azizi@endocrine.ac.ir
authors.forename: Fereidoun
authors.initials: F
authors.lastname: Azizi
authors.forename: Atieh
authors.initials: A
authors.lastname: Amouzegar
mesh_terms: D000328:Adult; D013956:Antithyroid Agents / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use; D002657:Child Development / Q000187:drug effects; D005260:Female; D005865:Gestational Age; D006801:Humans; D006980:Hyperthyroidism / Q000151:congenital / Q000188:drug therapy*; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007774:Lactation; D008431:Maternal-Fetal Exchange; D008713:Methimazole / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use; D050032:Postpartum Thyroiditis / Q000188:drug therapy; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy*; D011441:Propylthiouracil / Q000009:adverse effects / Q000493:pharmacokinetics / Q000627:therapeutic use; D012306:Risk; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000187:drug effects / Q000196:embryology
chemical_list: D013956:Antithyroid Agents; D008713:Methimazole; D011441:Propylthiouracil